In the process of transporting finished goods from a point of manufacture to a purchaser, it is generally inevitable that some damage will occur. The most common cause of such damage occurs during the loading and unloading of goods for transportation.
One industry in which it is desirable to reduce the damage caused to finished goods is in the shipping of paper products. Bulk paper rolls are most often transported via cargo ships from the mill in which they are made to their destination. To load the rolls into the ship's various holds, a crane operator picks up the rolls with a vacuum pick-up unit and lowers the rolls into position within the hold. In many instances, the crane operator is more than 150 feet above the floor of the hold and it is difficult for the operator to accurately gauge the position of the rolls above the hold floor. As a result, many rolls are inadvertently damaged because the crane operator lowers them too fast onto the hold floor or onto an existing layer of rolls in the hold.
A similar problem occurs when the cargo is moved horizontally within the hold. Because the operator cannot accurately gauge the distance between the rolls and the bulkhead of the ship, the rolls can be damaged as they are placed in position for transport.
Various mechanisms have been proposed to provide the crane operator with feedback concerning the relative position of the cargo and the hold. For example, closed-circuit television cameras or ultrasound schemes have been proposed to provide the crane operator with information concerning the position of the cargo relative to the hold or other stored cargo. However, such schemes have not proven workable because the operator is too busy to focus on a television screen or other gauge that provides the distance information.
To reduce damage to cargo, there is a need for a system that can provide a crane operator with the required feedback needed to accurately place cargo within a hold without requiring that the operator view extraneous sensors or monitors.